Simulating VHDL of an AVR8 soft processor

Okay, now we’re beginning to feel a bit like [Alice]. This tutorial shows you how to simulate VHDL code. This code is intended to run on an FPGA and includes a software-only version of the AVR 8-bit microcontroller core. Essentially, you’ll simulate VHDL code that simulates AVR hardware. Wrap your mind around that!

The code is intended to run on a Papilio Field Programmable Gate Array development board. We saw an early version of this board running the AVR8 core about a year ago. However, you don’t need to have any hardware to follow along and recreate this simulation yourself. It might be a great way to get your feet wet with FPGA programming before making that first hardware buy. Five different screencasts take you through the process of getting the AVR8 code, using an altered Arduino IDE for it, setting up a free version of Xilinx ISE to run the simulation, then setting it free and interpreting the data that the simulator spits out the other end.

Beginner Concepts: 595 shift register simulator

[Aaron] just finished building an online 595 shift register simulator. These inexpensive chips let you extend the number of devices that can be controlled by a single microcontroller. You see them in quite a few LED multiplexing projects, included the Ping Pong Clock that we recently built. But they can be a bit tricky to fully grasp if you’re not familiar with the hardware.

This simulator gives you a point-and-click interface for the five possible control lines on a 595 shift register. There are three pins that must be manipulated to use the device; the serial in, clock, and latch pins. The other two are for clearing the register, and enabling output and can be considered optional. You can choose to control these with a microcontroller in your own projects for more flexibility, but often they are tied to either VCC or GND (depending on the chip) when these features are unnecessary. Give this simulator a try and then take what you learned over to a solderless breadboard and see if you can write some firmware to produce the same results. If you’re still having trouble you can take a look at this 595 tutorial for further information.

Force feedback rig

Strap yourself in, it’s going to be a bumpy ride. No really, if you don’t believe us, check out the video after the break of this bouncing and rolling game system. [Shawn McGrath] built it to compliment the gaming experience for Dyad, an indie game for which he is a developer. His wife was kind enough to demonstrate the machine, which utilizes one motor to rotate the display and cockpit, and another to add vibration to the experience. The parts for the system were mostly salvaged, with the addition of a projector for the display and a PlayStation SixAxis controller to sense the motion of the rig. The motors are powered by a 600W computer PSU and controlled by an Arduino. It helps that [Shawn's] a developer because he was able to add feedback hooks to sync with the gameplay.

It’s not as intricate as the best flight simulators we’ve seen, but it will be fun for that next kegger.

[Read more...]

Logisim: Open source digital logic simulator

[Spi Waterwing] wrote in to make sure that we were aware of Logisim, a Java-based open source digital logic simulator. We’ve used Atanua quite a bit in the past but hadn’t heard of this program. It seems to have a pretty big educational following and right off the bat it’s got a feature we’ve always wanted, the ability to build your own ‘black box’ logic devices. That is to say you can build your own circuit out of logic gates and then package it into a part to be plopped into your next design. What it doesn’t have is the series logic chips that we’re used to with Atanua, but you can build your own with the black box feature if you really need that kind of functionality.

So grab a copy and try building that binary calculator project from last month.

Racing sim cockpit stores inside an ottoman

[Lyscho] built a racing simulator cockpit based on a PVC frame but it took up a lot of space when not in use. His second generation is built inside the frame of an ottoman, meaning it can be stored right under your feet.

The pedals are fixed in place, with some padding below to rest your heels on. The cockpit chair and steering wheel are both adjustable to suit different drivers. They use a routed groove along with wing nuts and bolts, making it easy to slide them for adjustments. The ottoman itself is [Lyscho's] own creation, which just needs power and USB when in use, and has a padded top when not in use.

If you can’t use a real car as the simulator this is fantastic alternative.

[via Make]

Four generations of motion simulators

We like a good flight simulator but often find the available control schemes lacking. [Roland] not only builds his own controls, but creates full cockpits that add physical motion to the mix. He completed his third generation cockpit last year.  It’s pictured above as well as in video after the break. That design uses a belt system to move the tricked out cockpit.

Now he’s started work on prototypes for generation IV. This time he’s using three Sarrus linkages to replace the belt system.  We saw these linkages yesterday in an extruder prototype and if they can handle the load they should work well for this application. Video of the prototype is embedded after the break but be warned, the lewd thrusting motions are not for the faint-of-heart. [Read more...]

New AVR simulator for Linux

simavr is a software simulator for the AVR line of microcontrollers. You might be asking why anyone would write this sort of thing considering the simulator provided with AVR Studio is a wonderful tool? Well, a lot of folks don’t run Windows and don’t wish to use that development environment even if Wine or Virtualbox could make it happen.

We haven’t tried it out ourselves yet. There is a discussion thread going that reports some positive results of using simavr with GDB and AVR Eclipse. It’s a new package, but so far it seems to have put its best foot forward. Currently there is support for ATtiny25/45/85, ATtiny13, ATmega48/88/168, andATmega164/324/644 chips. Several of the common on-chip peripherals are already supported with the others on the way.

Have you tried it out? Let us know what you think in the comments.

[IC Photo]